I have adapted the latest NiftyCorners into an easy to use Seaside Library.
http://www.html.it/articoli/niftycube/index.html
To Load:
Installer squeaksource
project: 'Jetsam';
install: 'Seside28Jetsam-NiftyCorners'.
enjoy
Keith
p.s. this is a standalone package and does not need the rest of the
Seaside28Jetsam addons.